The present invention relates to a device and method for automated collage formation from images and more particularly but not exclusively from non-uniform regions of interest identified from photographic images.
Collages have been a common form of artistic expression since their first appearance in China around 200 BC. Recently, with the advance of digital cameras and digital image editing tools, collages have gained popularity also as a summarization tool.
A collage is a work of the visual arts, made from an assemblage of different forms, thus creating a new whole. An artistic collage may include a variety of forms, such as newspaper clippings, papers, portions of other artwork, and photographs. While some define a collage as any work of art that involves the application of things to a surface, others require that it will have a purposeful incongruity.
This paper focuses on photo-collage, which assembles a collection of photographs by cutting and joining them together. A photo-collage can be used for art [Ades 1989], as well as for summarizing a photo collection, such as a news event, a family occasion, or a concept. A well-known example is album cover of the Beatles' “Sgt. Pepper's Lonely Hearts Club Band”.
Techniques for making collages were first used at the time of the invention of paper in China around 200 BC. Since then, these techniques have been used in various forms, including painting, wood, and architecture, in other cultures, such as Japan and Europe. In-spite of its early creation, the term “collage” was coined much later, by both Georges Braque and Pablo Picasso, at the beginning of the 20th century. These were the times when the use of collages made a dramatic appearance among oil paintings and became a distinctive part of modern art.
Manually creating a collage is a difficult and time-consuming task, since the pieces need to be carefully cut and matched. Therefore, automation could be a welcome tool, in particular for amateurs. Prior work on automating collage creation extracts rectangular salient regions and assembles them in various fashions. In one example, transitions between images are smoothed by graph cuts and alpha blending, which create aesthetic transitions between images. Nevertheless, non-salient regions, typically from backgrounds, cannot be eliminated.
The above approach to assemblage, while informative, does not match in spirit the way in which many artists construct collages. Artists commonly extract the expressive regions of interest, as noted by Henri Matisse “The paper cutouts allow me to draw with color”. This approach is expressed in numerous artistic collages, for instance see the pioneering works of “Just What Is It that Makes Today's Homes So Different, So Appealing?” by Richard Hamilton, and the “Dada Siegt” by Raoul Hausmann. The critical boundaries of the important information are considered significant and are thus maintained.
Methods for automatic creation of photo-collages were proposed only recently. A method known as AutoCollage, constructs a seamless collage from a large image set. In this work, rectangular salient image regions are stitched together seamlessly using edge-sensitive blending. In a method called picture collage, a 2D spatial arrangement of rectangular images is optimized in order to maximize the visibility of the salient regions. An improvement to picture collage exploits semantic and high-level information in saliency computation and uses a genetic algorithm for positioning. Google's Picasa features automatic collage generation of whole or cropped images, supporting different styles of compositions.